The invention concerns an apparatus for the manufacture of wood products from tree trunks, comprising feeding means for the reception of a tree trunk, said means being moveable together with the tree trunk along a feeding track laid substantially in the longitudinal direction of the tree trunk, said feeding track including a working zone with an arrayed series of tools, which are moveable into woodworking contact with the tree trunk in motion along the working zone. The objective of this invention is also a means in the installation for advancing the trunk adaptable in special configuration.
Saw frames and band saws are generally known from older technology with which a tree trunk is divided into boards by being moved on a carriage positioned in relation to a saw blade. The carriage is moveable in a fore and aft direction, and with each movement forward only one cut can be made. This older technology is now widely being abandoned in order to make way for modern splinter-chipping and profiling technology.
In installations where use is made of forming technology, a tree trunk is generally worked in a single pass whereby the trunk is, for example, first flattened along its sides, then corners at the tree trunk periphery are milled out, boards are separated from the sides, and the edged heart wood is, when possible, cut into further products like boards and beams. Such installations generally work automatically and are designed for a relatively high through-put.
The advance of the tree trunks through such installations is generally accomplished by means of stationary pairs of feeding rollers, partially aided by conveyers with corresponding dogs. The application of tools is carried out in the rule simultaneously from opposing sides.
These modern forming installations have not only the disadvantage for small production output that they require a very high level of capital cost but also that they work mostly with a fixed method of positioning and direction of insertion of the tree trunk into the installation. An attempt is usually made to position the trunks in the direction of their central axis, whereby the chippers for the leveling of the tree trunk have to chip off even more material because of the taper of the trunk the further down they engage with the lower end of the tree trunk.
Especially in South American countries the branches of the trunk are removed when the tree is young, so that the lateral growth of the trunk continues free of branches. The best clear wood is thus found in the outer portion of the trunk, while the heart still contains the branches of earlier growth.
It is therefore customary for reasons of quality in South American countries to separate wood products from the outer portion of the trunk not parallel to the central axis but rather parallel to the outer surface line. Modern forming installations are not designed for this procedure.
The invention is thus intended as a mechanism for the production of wood products, which on the one hand employs modern forming technology and on the other hand is cost effective for smaller businesses and smaller through-put, and beyond that also allows for a method of operation in which a tree trunk can be processed from one side or several sides substantially parallel to the outer surface line.
This task is carried out with a mechanism invented basically as according to the characteristic features of patent claim 1.
From U.S. Pat. No. 3,457,978 a forming installation is previously known in which a tree trunk is clamped on a carriage on a track and transported past several work stations in series. The purpose of this known installation is, however, to allow for central control of the finished and waste products. The track is formed as sort of closed circuit around the equipment, which makes for a very costly installation in that it contains as many work stations as are required for the various steps of processing and is thus intended for a continual through-put of wood. It has no way to mount a tree trunk other than in its axial direction.